Bleach leaves to much salt in the pool?

mustang68

Active member
Nov 1, 2009
33
Ok I haven't been here in months but I do have some questions. I was told by the pool store, you know the place of 1000 different opinions, that bleach leaves to much salt in the pool and raises total suspended solids after time. In effect he said that I would have to drain the pool every year no matter what. That didn't sound right. I follow the outline here and use bleach. living in TX I am having to add bleach every night and again when I get home at about 4 p.m. By that time its almost at 0. I dont mind the process but wanted to be sure this sounds ok.

Second I have an automated clorinator in line with my pump. Can I just pour bleach into it and use it that way. With the settings I can basically control the flow or can I?
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
Re: Can I maintain FC level with bleach?

It sounds like you have too high a chlorine demand. You should be able to add chlorine once a day and not need to add it twice a day. You should Perform the Overnight FC Loss Test to make sure you aren't fighting a nascent algae bloom. If you are mostly losing chlorine during the day, then your Cyanuric Acid (CYA) level is probably too low.

As for rising salt levels, ALL sources of chlorine add salt because when the chlorine gets used up / consumed it results in salt. For every 10 ppm FC added by ANY source of chlorine, it will result in 8.2 ppm salt from the consumed chlorine that turns into chloride salt. With bleach, chlorinating liquid, and lithium hypochlorite, there is an additional 8.2 ppm salt upon addition so the net total result is 16.5 ppm. However, even at 3 ppm FC per day chlorine usage for 6 months this is around 890 ppm added salt if you had no water dilution and would not normally require a water change after only one year. If your chlorine usage is lower or you have water dilution or a shorter swim season, the build-up will be less.

If you were to use Trichlor pucks with the same chlorine usage, the CYA level would increase by 330 ppm in 6 months with no dilution. This would obviously be far worse. If you were to use Cal-Hypo with the same chlorine usage, the Calcium Hardness (CH) would increase by at least 380 ppm which also wouldn't be very good though not as bad as the CYA increase.

Richard
 

Bama Rambler

Mod Squad
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Jun 22, 2009
23,371
SouthWest Alabama
Re: Can I maintain FC level with bleach?

Mustang -- If you will post a full set of test results we may be able to help with your chlorine usage.

As Richard said, your CYA may actually be too low for your area.
 

geekgranny

LifeTime Supporter
Aug 20, 2009
1,358
North Central Texas
Re: Can I maintain FC level with bleach?

Bama Rambler said:
Mustang -- If you will post a full set of test results we may be able to help with your chlorine usage.

As Richard said, your CYA may actually be too low for your area.
In Texas with full sun on pool about 7 hrs/day; partial for about 2-4 more. I like to keep my CYA between 50-60. Makes bleach additions more predictable. I add 182 oz 6% every two days and only test for FC once or twice a week. If the bather load increases or more organics than normal enter pool I'll check FC more often. Usually check pH every other day as I maintain pH at 7.2 to help the sequestrant help release the calcium scale. (It's working :-D ) If we've had a cloudy day or more or rain I check the FC more. Knowing my pool the 182 oz is just right every other day under normal sunny circumstances. My main bather load is several big country dogs getting in and out of the pool many times a day after playing in our "dust bowl" and woods.

My target is to go a little above the target high of 8 FC (I put 54 for CYA in the calculator) so after additions it is usually around 9-10. That's well below shock level.

I do have one question. Should we be putting an estimated number in for salt, in the Pool Calculator, as it does build up over time? I'm maintaining a CSI of about -0.33, on purpose. When I put in several numbers for salt it doesn't affect the CSI. I just put in 1000 for salt and it took the CSI down to -0.41. Playing with the numbers is looks like it would take a bunch of bleach over a long period to actually affect the CSI. I guess for my size pool and lots of splash out and draining for rain, some backwashing, salt would probably never become critical for CSI in my pool. But are there any circumstances where salt levels, in a non SWG pool, would be of concern?

gg=alice
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
It takes a lot of salt to move the CSI so it's not a big concern and normally it's just important to distinguish between an SWG and a non-SWG pool. Even with a high 3 ppm FC per day chlorine usage, this would only increase salt by around 890 ppm if there were no water dilution. In a plaster pool, the starting CH and TA usually results in a TDS of around 500 ppm; in a vinyl pool it could be less if the fill water is low in CH. Over time, most non-SWG pools don't get much higher than 1000 ppm with normal water dilution though those with cartridge filters and no summer rains can get closer to 1500 ppm if they have high daily chlorine demand. The CSI from 500 to 1000 ppm salt decreases by 0.06, from 1000 to 1500 it decreases an additional 0.05, from 1500 to 3000 it decreases by an additional 0.1. So this isn't a big deal unless you are way off in the numbers using SWG numbers for a fresh-fill pool or vice versa and even then it's a difference of 0.21 in the index.
 

rastoma

Well-known member
May 17, 2009
249
Jasper, TN
mustang68 said:
Ok I haven't been here in months but I do have some questions. I was told by the pool store, you know the place of 1000 different opinions, that bleach leaves to much salt in the pool and raises total suspended solids after time. In effect he said that I would have to drain the pool every year no matter what.
I would never step foot in that door again. He absolutely lied with a straight face to you, knowing that the chlorine you are using is 100% identical to the liquid chlorine he sells at the pool store.

There is no chemical NAMED bleach. Bleach is an AKA... AKA=also known as.... of hypochlorite..... AKA chlorine.
 

Txmat

LifeTime Supporter
Jun 18, 2010
424
San Antonio
Re: Can I maintain FC level with bleach?

geekgranny said:
Bama Rambler said:
Mustang -- If you will post a full set of test results we may be able to help with your chlorine usage.

Usually check pH every other day as I maintain pH at 7.2 to help the sequestrant help release the calcium scale. (It's working :-D )

gg=alice
Geekgranny, What do you mean by a "sequestrant help release the calcium scale"?
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
This doesn't always happen, but sometimes when you add sequestrant and the PH is relatively low, calcium scale can soften up and come off. This happens most often on calcium scale that has formed recently, or when the PH is very very low.
 

Txmat

LifeTime Supporter
Jun 18, 2010
424
San Antonio
Thanks Jason. I thought there might be a product that will reduce calcium that I did not know about. As far as I know the only way to reduce calcium levels is by water replacement.
 

mustang68

Active member
Nov 1, 2009
33
Re: Can I maintain FC level with bleach?

geekgranny said:
Bama Rambler said:
Mustang -- If you will post a full set of test results we may be able to help with your chlorine usage.

As Richard said, your CYA may actually be too low for your area.
In Texas with full sun on pool about 7 hrs/day; partial for about 2-4 more. I like to keep my CYA between 50-60. Makes bleach additions more predictable. I add 182 oz 6% every two days and only test for FC once or twice a week. If the bather load increases or more organics than normal enter pool I'll check FC more often. Usually check pH every other day as I maintain pH at 7.2 to help the sequestrant help release the calcium scale. (It's working :-D ) If we've had a cloudy day or more or rain I check the FC more. Knowing my pool the 182 oz is just right every other day under normal sunny circumstances. My main bather load is several big country dogs getting in and out of the pool many times a day after playing in our "dust bowl" and woods.

My target is to go a little above the target high of 8 FC (I put 54 for CYA in the calculator) so after additions it is usually around 9-10. That's well below shock level.

I do have one question. Should we be putting an estimated number in for salt, in the Pool Calculator, as it does build up over time? I'm maintaining a CSI of about -0.33, on purpose. When I put in several numbers for salt it doesn't affect the CSI. I just put in 1000 for salt and it took the CSI down to -0.41. Playing with the numbers is looks like it would take a bunch of bleach over a long period to actually affect the CSI. I guess for my size pool and lots of splash out and draining for rain, some backwashing, salt would probably never become critical for CSI in my pool. But are there any circumstances where salt levels, in a non SWG pool, would be of concern?

gg=alice
Well I am using about the same amount of chlorine 6% that you are. My last check my CYA was about 25 which I imagine is low. Should I stick some Trichlor pucks in there for a day or two and raise the level?
 

geekgranny

LifeTime Supporter
Aug 20, 2009
1,358
North Central Texas
Re: Can I maintain FC level with bleach?

mustang68 said:
Well I am using about the same amount of chlorine 6% that you are. My last check my CYA was about 25 which I imagine is low. Should I stick some Trichlor pucks in there for a day or two and raise the level?
I would suggest as the very first thing to get a good test kit to determine if you need to shock your pool first. Of course with the blazing sun and too little CYA to protect your FC you will be losing a lot of, if not all of your FC daily. Especially when that happens you are more prone to get high CCs in your pool if your FC level falls below your target for even a short time. You may need to shock first. Shocking uses much less chlorine when the CYA level is relatively low. But as soon as you are finished shocking you need to get the CYA up ASAP.

When was the CYA tested and who did it?. You could be lower than that especially if you have been letting water out because of rain and/or backwashing. If you have been using Trichlor, exclusively it may be higher. If it is too high you might not be using enough chlorine for your CYA level.

Puck will take a long time to get your CYA up.Your pool is less than half the size of mine. Either organics or sun or both are eating up a lot of your chlorine. I've had more stable chlorine levels by raising my CYA. Right now it is 40 from letting out rain, backwashing, and overfilling a couple of times. I'm off to Walmart in a bit to pick up CYA, calcium, Baking Soda, and Metal Control. All of those levels reduce sigificantly when water has to be added back into the pool too. I also have a lot of splash out from the dogs so over time the CYA, and every thing else, is lost to all those things. The HTH brand is my favorite stabilizer/conditioner (CYA) purchased at Walmart. It dissolves the fastest of any I've used. It cost about $15-16 for 4 lbs. BUT..... again you need to know the numbers of your water. The only way to do that is a good test kit. Pool stores are notoriously way off, much of the time. In the short run you can get a 6 way test kit from Walmart that is about $20; drops not strip. It has enough reagent in it for two CYA test.

Please test and post your numbers before proceeding so that members can guide you. If you don't know they what's and whys you could go around in circles trying to manage your pool. Again, there could be several reasons you are using so much chlorine; over double what I use in my pool. The CCs in my pool have never gotten over .5 in the year that I've been using the BBB method. This has been really easy to manage with a good test kit and a few minutes every other day; occasionally every day but most often every other. (That doesn't include taking the Aquabot out every day to put a clean bag in. I can only get a few hours use out of one fine bag/24 hour period. That right there is a good indication of all the dust/dirt/soil muck that goes into my pool daily. There is much less sand going in than the other stuff.)

When you get a solid hold on why you are using so much chlorine and take care of that, you can then raise your CYA if needed. In our sun and heat I really think 50 is a good target to start with. Then after the CYA has had time to register on test you will know just how much more to add to reach a target of 60 if that is what you want to do.

BTW.... my bleach addition amounts don't vary in the extremes when CYA is in the 40-60 range. As I stated earlier, my usual guesstimate of one 182 oz % is normal but sometimes I add more or less depending on what my FC level reads when I do the test a few times a week. I'll then add that amount for a few days and readjust with next test. I would rather have the FC a bit over target than it to get too low at any time. A very important thing to understand when I talk about guesstimating is that I never let the CCs get above .5. When we have to be both gone for over over 12 hours or so I have to have a dog sitter so she can add bleach but if I didn't need sitter then I certainly would use the pucks in floater. Jug dumping is just so easy. The only time I've used algaecide in decades is when I did the AA treatment and had to lower the FC.

gg=alice
 

mustang68

Active member
Nov 1, 2009
33
Re: Can I maintain FC level with bleach?

I'm getting the water tested today so I will have some baseline numbers. I also need a better test kit but dont want the most complicated one. Any recommended ones.

I should note that I have had not one problem with my pool except a metal stain that was a result of the pool contractor setting up my pool chemistry for me in the beginning and screwing it up. I have never had a CC reading above 0. My only concern is that I am using chlorine at such large amounts. I truly believe it is just the sun doing it and now I believe to low of a CYA. Though in my mind I thought no CYA was a good thing. I will get those numbers very soon.
 

mustang68

Active member
Nov 1, 2009
33
Here are the numbers I got from the pool store test. I do not have a kit yet so I have to use them for now.

FC=4.0
TC=4.0
cc=0
pH=7.6
hardness=not run
Alkalinity= 100
CYA=40
copper=0
TDS=not run
Phosphates=1000

The only issue they noted was the phosphates. I was surprised by that number but there it is. They recommended 1.5 liters of phosfree to bring it down to 0. follow up with one cap full a week. So i was able to get my CYA up a little with some trichlor tabs. I wont use those anymore as I prefer BBB. As long as I have enough stabilizer that should help..right? So let me know what my numbers tell you.
 

JasonLion

TFP Expert
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LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
Your numbers look good.

I would just ignore the phosphate level. Phosphates won't be an issue as long as your maintain your FC level correctly.

It would be nice to know your CH level, though there isn't any rush on that. The recommended CH level for fiberglass is between 220 and 320.
 

mustang68

Active member
Nov 1, 2009
33
JasonLion said:
Your numbers look good.

I would just ignore the phosphate level. Phosphates won't be an issue as long as your maintain your FC level correctly.

It would be nice to know your CH level, though there isn't any rush on that. The recommended CH level for fiberglass is between 220 and 320.
Also any recommended test kits that include a test for CH level. At this point I dont want to trust the two local pool stores anymore than I have already. Everytime I go in they come up with a new way to try and sell me something expensive.
 

Txmat

LifeTime Supporter
Jun 18, 2010
424
San Antonio
Mustang, I am using the test kit from TF Test Kits. The link is listed in Pool School and in the signature of many folks on this site such as JasonLion above. It tests FC, CC, TA, CH, CYA, PH. In short all the tests you may need except salt and borates. If you need those he sells strips for them. I also recommend you get the automatic stirrer. It is not necessary, but it sure makes it easier. I really like the kit and it is by far the best I have ever had.
 

PaulR

LifeTime Supporter
Jan 11, 2009
1,966
Cupertino, CA
Regarding salt levels, I mostly use bleach except I use trichlor for vacations and 10 or so tabs in the spring to bring CYA back up a little. It happens I measured my salt level just a year ago at 500, and today is around 900, with no intentional dilution (just winter rains).
--paulr
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
PaulR said:
It happens I measured my salt level just a year ago at 500, and today is around 900, with no intentional dilution (just winter rains).
The annual average precipitation in Cupertino is around 23" so if the pool had an average depth of 4.5' then that would be around 43% dilution, but closer to continuous dilution so equivalent to a 35% one-time dilution (though some of the winter rains probably don't overflow and just refill from evaporation). So the salt increase might have been around 115 ppm per month for 3 months to get to 845 ppm, then 35% dilution down to 550 ppm, then winter season (assuming minimal chlorine addition during winter), then 115 ppm per month for 3 months to get to 895 ppm. 115 ppm per month salt from bleach or chlorinating liquid would be 115/1.65/30 = 2.3 ppm FC per day which seems reasonable. If your season was longer, then your daily chlorine usage is probably lower. My example in my earlier post used a conservatively high 3 ppm FC per day and no water dilution.
 

mustang68

Active member
Nov 1, 2009
33
So which works for me. I dont want the one that will unlock the secrets of all pool chemistry. I just one that covers most things and is easy to use.

1) The TF-100 Test Kit - the finest, most comprehensive swimming pool test kit you can buy.

2) The TF-100 XL - for clearing green pools (it contains more of what you need the most) or converting your pool from baquacil.

3) The TF-50 - A smaller, economical version of the TF-100 with smaller quantities of reagents.

4) The Taylor K-2006, a great kit with similar tests but presented in a different format.

As soon as I get feedback I will purchase one. Thanks!